1. Field of the Invention
This invention relates to an electrochemical process and apparatus for the recovery of precious metals, particularly silver and gold, from ores, including not only newly mined materials but also tailings, slags and dumps remaining from previous recovery and mining operations. More specifically, the present invention relates to improvements upon processes and apparatuses for electrolytic recovery of precious metals from ores by means of cyanide complexing agents.
2. Description of the Prior Art
A variety of processes and apparatuses have been developed for electrochemically treating ores for the purpose of recovering their precious metals, particularly silver and gold. Many processes, as exemplified by U.S. Pat. No. 601,068 to Von Siemens, use cyanidation treatments. Notwithstanding considerable efforts devoted to the development of various electrochemical processes and apparatuses for recovering precious metals, none have been capable of a level of performance which makes them commercially practical for processing low grade new ores, or for reprocessing the vast quantity of low grade precious metal-containing tailings, slags and dumps which are the remnants of previous recovery and mining operations. One prominent drawback of prior electrochemical recovery techniques is the slowness with which they permit recovery. Extraction of precious metals during conventional cyanidation typically takes 3 to 24 hours, necessitating a massive apparatus if worthwhile amounts of precious metal are to be obtained from low grade ores. For these and other reasons, electrochemical techniques for recovering precious metals from ores have not been commercially practical or successful.